Snowmobile Vehicle

Environmental impact
The environmental impact of snowmobiles has been the subject of much debate. Governments have been reacting slowly to noise and air pollution, partly due to lobbying from manufacturers and users of snowmobiles. For instance, in 1999, the Canadian government adopted the Canadian Environmental Protection Act, but the set of rules governing pollution emissions for off-road vehicles was only released in January 2005. Another example of regulation, only four-stroke snowmobiles are allowed in Yellowstone National Park since a bylaw was recently passed to minimize CO2 emissions and noise. In Yellowstone, snowmobiles account for 80% of total hydrocarbons emissions and 50% of carbon monoxides emissions during the winter months. Although less than 2% and 1% overall annually respectively. In winter, snowmobiles only are allowed to ride on the unplowed roads used in the summer in the park. This impact accounts for less than 1% (.002%) of the park area.
• Air
Most snowmobiles are still powered by two-stroke engines, although Alpina Snowmobiles and Yamaha have been using four-strokes respectively since 2002 and 2003. However, in the last decade several manufacturers have been successful in designing less polluting motors, and putting most of them in production. Yamaha and Arctic-Cat were the first to mass produce four-stroke models, which are significantly less polluting than the early two-stroke machines. Alpina offers a 4-stroke EFI engine equipped with a catalytic converter and state of the art dual oxygen-probe. Bombardier's E-Tec two-stroke motors emit 85 percent less pollutants than previous carburated 2-strokes. Polaris has developed a fuel-injection technology called "Cleanfire Injection" on their 2 strokes. The industry is also working on direct injected "clean two strokes" which are actually an improvement on carbureted four strokes in terms of NOX emissions.